Hydrocarbon Reservoirs Management
TEMPLE N CHIKWE; Remy Ukachukwu Duru
Abstract
The Asphaltene and metal naphthenate components of crude oil samples from ten different wells within an oil reservoir were determined using different analytical techniques. The asphaltene content was determined by gravimetric analyses while the metal naphthenate components were determined by obtaining ...
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The Asphaltene and metal naphthenate components of crude oil samples from ten different wells within an oil reservoir were determined using different analytical techniques. The asphaltene content was determined by gravimetric analyses while the metal naphthenate components were determined by obtaining the metal ion concentration of the produced water and the naphthenic acid concentration of the crude using Atomic absorption spectrometer (AAS) and potentiometric titration respectively. Results obtained showed that the asphaltene content of the crude samples ranges from 2.0000 – 8.000 %w while the naphthenic acid concentration indicated by the total acid number (TAN) ranges from 0.3000 – 1.4600 mg/KOH/g. All the crude samples possess asphaltene components as well as the propensity to form calcium and sodium naphthenate scale deposits having a Ca2+ concentration between 32.5000 – 94.5000 mg/L and a Na+ concentration between 27.7 – 105.1 mg/L respectively, however the formation of naphthenate scale deposits is highly dependent on the pH of the produced water of the crude which makes well FT01 less likely to form naphthenate scales since it has a pH < 6. Both asphaltene and naphthenate deposits are directly proportional to the specific gravity of the crude and inversely proportional to the API gravity implying that both components reduce the quality of the crude. Asphaltene and metal naphthenate solid deposits in the crude can cause a lot of flow assurance difficulties such as, blocking of expedition lines, pore plugging, wettability, crude oil parameter alteration, as well as reduction in oil recovery.
Hydrocarbon Reservoirs Management
Charles Ikenna Oraegbunam; Leo Osuji; Mudiaga Onojake; Selegha Abrakasa
Abstract
The organic geochemical characterization of crude oil samples from the oil fields of the Niger delta was carried out using gas chromatography–-mass spectrometry (GC–-MS) to genetically characterize the oil samples in terms of their biomarker composition. Geochemical characteristics such as ...
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The organic geochemical characterization of crude oil samples from the oil fields of the Niger delta was carried out using gas chromatography–-mass spectrometry (GC–-MS) to genetically characterize the oil samples in terms of their biomarker composition. Geochemical characteristics such as depositional environments, kerogen type, and source of organic matter were analyzed using aliphatic biomarkers as a supporting tool. Five samples were randomly collected from Tebidaba, Clough Creek and Azuzuama fields in Bayelsa State, Nigeria. The saturated hydrocarbons were analyzed using GC–MS. The n-alkanes, isoprenoids, biomarkers hopanes, and steranes fingerprints were extracted from chromatogram for m/z 57, 191, 217 values respectively. The results revealed that the five studied samples were characterized by C29 sterane predominance and the presence of oleanane, depicting organic matter with vascular land plant material inputs and a deltaic contribution. Ternary plots showed that the oils were deposited in an estuarine environment. The pristane (Pr) /nC17 versus phytane (Ph)/nC18 showed that TEB 08 and WELL 2 are in the anoxic environment inferring kerogen II and a mixture of types I and II respectively. TEB 12, CCST, and AZU ST has kerogen type III deposited in an oxic environment.
Petroleum Engineering – Reservoir
Abiodun Ogbesejana; Oluwadayo Sonibare; Zhong Ningning; Oluwasesan Bello
Abstract
Crude oils and source rocks from the northern and offshore Niger Delta basin, Nigeria, have been characterized by gas chromatography-mass spectrometry in terms of their origin and thermal maturity based on the distribution of chrysene and its derivatives. The crude oils and source rocks were characterized ...
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Crude oils and source rocks from the northern and offshore Niger Delta basin, Nigeria, have been characterized by gas chromatography-mass spectrometry in terms of their origin and thermal maturity based on the distribution of chrysene and its derivatives. The crude oils and source rocks were characterized by the dominance of chrysene over benzo[a]anthracene. 3-methylchrysene predominated over other methylchrysene isomers in the oils, while 3-methylchrysenes and 1-methylchrysenes were in higher abundance in the rock samples. The abundance and distribution of chrysene and its derivatives allow source grouping of the oils into three families. However, this grouping disagrees with the results obtained from well-established aromatic source grouping parameters. The maturity-dependent parameters computed from chrysene distributions (MCHR and 2- methylchrysene/1-methylchrysene ratios) indicated that the oils have a similar maturity status, while the rock samples are within an immature to early oil window maturity status, which was further supported by other maturity parameters computed from the saturate and aromatic biomarkers and vitrinite reflectance data. The abundance and distribution of chrysene and its derivatives were found to be effective in determining the thermal maturity of crude oil and source rock extracts in the Niger Delta basin, but they may not be a potential source-dependent biomarker in the crude oils and rock extracts from the basin.